Process of vulcanizing rubber.



PATBNTED AUG. 4, 1903-.

A. 0. BOURN. PROCESS 'OF VULGANIZING RUBBER.

APPLIOATIOH FILED JAN. 2, 1903.

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UNITED STATES Fatented August 4, 1903.

AUGUSTUS O. BOURN, OF PROVIDENCE, RHODE ISLAND.

PROCESS OF VULCANIZING RUBBER.

SPECIFICATION forming part of Letters Patent No. 735,059, dated August 4, 1903.

Application filed January 2,1903. Serial No. 137,500. (No specimens.)

To aZZ whom it may concern.-

Be it known that I, AUGUSTUS O. BOURN, a citizen of the United States, residing at Providence, in the county of Providence and State of Rhode Island, have invented certain new and useful Improvements in Processes of Vulcanizing Rubber, of which the following is a specification.

In vulcanizingarticles of india-rubber composition or of compositions embodying vulcanizable gums in the presence of air or other gas it has been common to heat the vulcanizing element either by a steam-jacket surrounding the chamber in which the air or other element is inclosed or by heating-coils inside the chamber. In most instances the vulcanizingchambers are of large dimensions, so as to permit the introduction of a large number of articles at one time, and under any of the processes and means heretofore employed it has been found impracticable to maintain a uniform temperature throughout the chamber, the result being that some of the articles or some portions of the articles are treated diderently from the others and the articles are not uniformly vulcanized. To avoid these objections, I maintain an enforced slow circulation of the vulcanizing element into and out of the vulcanizing-chamber, as fully set forth hereinafter, and as illustrated in the accompanying drawings, in which- Figure l is a sectional plan View of a vulcanizing apparatus illustrating my improvements. Fig. 2 is a side elevation. Fig. 3 is a side elevation illustrating the means em ployed where the vulcanizing is effected under pressure.

The vulcanizing-chamber is contained within a suitable casing A, open at one side to permit the introduction of the articles and capable of being then closed substantially air-tight, the articles being suspended generally within the chamber from suitable supports. iVhen the vulcanizing element, as air, is to be heated within the vnlcanizingchamber, this may be effected through the medium of a coil of steam-pipes B, arranged at the bottom of the chamber and communicating with a boiler C, any suitable means being employed to insure a proper circulation of the steam in contact with the coil 13, which serves to heat the air. The air or other gas is drawn from a pipe 1, connected with a series of perforated pipes 2, arranged near the bottom of the vulcanizing-chamber, and is forced into the chamber. through another series of perforated pipes 3 near the top, the pipe 1 communicating with the inlet of a fan, blower, pump, or other forcing apparatus F, and the pipe 3 communicating with a discharge-pipe 4, leading from the outlet of the apparatus F. As shown, the fan F is connected to be driven by an electric motor M; but any other suitable means may be used.

Where the vulcanizing element is to be externally heated, a heating-coil 6, Fig. 3, may be arranged within a furnace G outside the vulcanizing-chamber. The air is positively circulated by a pump P, the inlet-pipe of which communicates with the perforated pipe 2 atthe bottom of the chamber and the outlet-pipe with the coil 6, and a perforated coil 3 at the top of the chamber communicates with the top of the coil 6. 'In this construction the chamber is in a casing adapted to any suitable internal pressure, and a forcepump is employed which may be driven from any suitable source and by means of which the air or other vulcanizing element may be raised to and maintained under any desired pressure for any desired time and in enforced circulation. 1

Whatever may be the heating and circulating means employed, it will be seen'that such an enforced circulation is maintained as will insure a uniform vulcanizing' of all of the articles throughout the entire chamber and that there is such a constant movement of the vulcanizing element that it will pass through all the spaces between the articlesin such manner as to promote a uniform result with said articles packed closely together. I have found, therefore, that by the use of my improvement I can make use of a vulcanizingchamber much smaller than usual or secure a much larger product from a chamber ofusual size and that I can heat the air-supply and force it from a single blowing or pumping apparatus into and through a number of vulcanizing-chambers without the necessity of using a heating-coil in each chamber, as heretofore.

By dispensing with the use of heating-coils within the chambers I secure other advantagesfirst, an increasein the available space for the reception of goods owing to the absence of the coil itself, and, secondly, an increase in the available space owing to the fact that when a heating-coil is employed the excessive radiation of heat prevents the arranging of articles in close proximity to the coil and the chamber must be large enough to arrange the coil distant from the articles.

When the air is heated outside of the chamber and forced into and through the latter, either intermittently or in a practically continuous current, the whole area of the chamber may be practically used for stowage, a practically uniform heat may be maintained throughout the chamber, and the articles can be uniformly vulcanized even when arranged so closely together that their vulcanization could not be effected by ordinary means.

It will be understood that I have illustrated the use of coils, perforated pipes, 850., merely to show means for carrying out my invention and that the circulation maybe efiected and the advantages enumerated obtained where jackets or other heating means are employed,

and'as other aeriform or gaseous substances may be used instead of air I have designated the same by the term vulcanizing element, so as to include any gas by which the articles to be vulcanized may be enveloped and which may be maintained to enforce circulation. It will of course be understood that a rapid or violent circulation is not generally desirable and that it is sufficient to maintain a steady slow movement of the vulcanizing element over the articles.

Without limiting myself to the use of the apparatus shown, I claim- 1. The within-described improvement in vulcanizing articles of rubber and allied gums, the same consisting in subjecting the articles to an enforced current of a heated gaseous vulcanizing element, substantially as set forth.

2. The within-described improvement in vulcanizing articles of rubber and allied gums, consisting in heating a gaseous vulcanizing element and in then forcing it into and out of a chamber containing the articles to be vulcanized, substantially as set forth.

3. The within-described improvement in vulcanizing rubber articles consisting in subjecting the articles in a closed chamber to a current of vulcanizing element under heat and pressure, substantially as set forth.

4. The within-described improvement in vulcanizing articles of rubber and allied gums, consisting in subjecting the articles to an elevated temperature for a time suflicient to vulcanize the same, and to an enforced current of a heated, gaseous element, substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

AUGUSTUS O. BOURN.

Witnesses:

M. L. LAKE, F. R. MCKENNA. 

